add charset rules

Author: andersonjoseph

lib/rules/string.js

@@ -1,18 +1,15 @@
 "use strict";
 
 const NUMERIC_PATTERN = /^-?[0-9]\d*(\.\d+)?$/;
+const ALPHA_PATTERN = /^[a-zA-Z]+$/;
+const ALPHANUM_PATTERN = /^[a-zA-Z0-9]+$/;
+const ALPHADASH_PATTERN = /^[a-zA-Z0-9_\-]+$/;
 
 module.exports = function checkString(value, schema) {
 	if (typeof value !== "string") {
 		return this.makeError("string");
 	}
 
-	/* TODO: charset
-	 	alpha: /^[a-zA-Z]+$/
-		alphaNum: /^[a-zA-Z0-9]+$/
-		alphaDash: /^[a-zA-Z0-9_\-]+$/
-	*/
-
 	const valueLength = value.length;
 
 	if (schema.empty === false && valueLength === 0) {
@@ -43,8 +40,20 @@ module.exports = function checkString(value, schema) {
 		return this.makeError("stringEnum", schema.enum);
 	}
 
-	if (schema.numeric === true && !RegExp(/^-?[1-9]\d*(\.\d+)?$/).test(value) ) {
-		return this.makeError("stringNumeric", 'A numeric string', value);
+	if (schema.numeric === true && !NUMERIC_PATTERN.test(value) ) {
+		return this.makeError("stringNumeric", "A numeric string", value);
+	}
+
+	if(schema.alpha === true && !ALPHA_PATTERN.test(value)) {
+		return this.makeError("stringAlpha", "An alphabetic string", value);
+	}
+
+	if(schema.alphanum === true && !ALPHANUM_PATTERN.test(value)) {
+		return this.makeError("stringAlphanum", "An alphanumeric string", value);
+	}
+
+	if(schema.alphadash === true && !ALPHADASH_PATTERN.test(value)) {
+		return this.makeError("stringAlphadash", 'An alphadash string', value)
 	}
 
 	return true;